In most hydraulically actuated fuel injection systems, an actuation fluid, such as fuel or lubricating oil, is used as a hydraulic medium to actuate the individual injectors for each injection event. As two differently pressurized fluids (low pressure fuel and high pressure actuation fluid) must necessarily be provided to the fuel injectors in such a system, there must be adequate space in and around the engine for the various components necessary to supply the differently pressurized fluids which are themselves often different types of fluid (i.e. fuel and lubricating oil). In some engines, particularly relatively large diesel engines, it is often possible to incorporate separate actuation fluid and fuel fluid rails into the engine head. However, in many smaller type diesel engine applications, there is simply not enough space to incorporate both fluid rails into the engine head. Thus, in these cases, a separate external actuation fluid rail must often be mounted on the engine, and separate actuation fluid supply pipes from the rail must be attached to each individual injector. Space constraints are especially pronounce in those cases where a hydraulically actuated fuel injection system is retrofitted on a diesel type engine that originally used cam actuated fuel injectors. Still another complication in clamping fuel injectors to the actuation fluid supply pipes is the need to make the individual clamps accessible for maintenance purposes.
Apart from the space constraint and accessibility problems encountered in clamping hydraulically actuated fuel injectors to the actuation fluid supply pipes is the problem of how to avoid distortion to the injectors through the use of the clamping mechanism. Because the actuation fluid supply to each injector is at a relatively high pressure, relatively high clamping loads are necessary in order to insure against leakage of actuation fluid. In some cases, these relatively high clamping loads can cause internal distortion to the fuel injector, which can lead to seizing of the injector, even in those cases where space constraints are not particularly significant. Thus, even ignoring space constraints and accessibility, the actuation fluid supply clamp must provide an adequate clamping force to prevent against leakage, but must do so in a way that minimizes internal distortion in critical areas within the fuel injector.
The present invention is directed to overcoming one or more of the problems as set forth above.